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[Display omitted] • BiOBr was prepared as negative material for aqueous alkali battery. • Hierarchical microspheres assembled by laminas was constructed. • Mesoporous structure with high surface area and electrolyte affinity was ensured. • High capacitive and rate capability negative electrode was yielded. Bismuth (Bi) based compounds are promising negative materials in aqueous alkali batteries (AABs) for the 3-electron redox chemistry of Bi element within low potentials, the exploration of new Bi-based negative materials is still a meaningful work in this field. Herein, a hierarchical bismuthyl bromide (BiOBr) microspheres material assembled by laminas was prepared via solvothermal reaction and attempted as negative battery material for AAB. The pronounced redox reactions of Bi species in low potential enable high battery capacity, and the porous texture with high hydrophilicity facilitates diffusion of OH– and participation in faradaic reactions. When used as negative battery electrode, the BiOBr could offer decent specific capacity (C s , 190 mAh g−1 at 1 A g−1), rate capability (C s remained to 163 mAh g−1 at 8 A g−1) and cycleability (85% C s retention after 1000 charge–discharge cycles). The AAB based on BiOBr negative electrode could export an energy density (E cell) of 61.5 Wh kg−1 at power density (P cell) of 558 W kg−1 and good cycleability. The current work showcases valuable application expansion of a traditional BiOBr photocatalyst in battery typed charge storage. [ABSTRACT FROM AUTHOR]

To develop the urgent requirement for high-rate electrodes in next-generation lithium-ion batteries, SnO2-based negative materials have been spotlighted as potential alternatives. However, the intrinsic problems, such as unremarkable conductivity and conspicuous volume variation, make the rate capability behave badly at a fixed current density. Here, to solve these issues, we demonstrate a new and facile strategy for enhancing their cyclic stability, and a kind of rutile SnO2-x nanoparticles with abundant oxygen vacancies (OVs) is fabricated through a hydrothermal process combined with aluminothermic treatment method without carbon coating. In addition, the growth of initial grains is restrained after aluminothermic treatment, which also reduces the unexpected polarization of negative electrodes. As a result, the as-synthesized SnO2-x anode material reveals a remarkable reversible capacity of 380 mAh g−1 at 0.5 A g−1 and exhibits promising capacity of 267 mAh g−1 at 2.0 A g−1. The improved capabilities and cycling life can be ascribed to the positive effect of introducing OVs. Moreover, the strategy has an important role in the design of tin-based negative materials of the next-generation lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Chitosan, extenders anointed and in-situ synthesis method were used to synthesize anode-composite lead-carbon batteries.SEM, EDS, BET and RM were used to characterize and analyze the morphology of carbon materials.The results show that chitosan-carbon has non-crystal structures.Its pore size distribution is between 5-10nm.Specific surface area reaches to 487.4m2/g.The negative composite material electrode is mixed with a conductive agent to produce pastel.Pb-C analog battery was assembled.Electrochemical workstation is used to test chronoamperometry curves, electrochemical impedance spectroscopy so as to evaluate the possibility of in-situ synthesis anode composite material and its potential value of practical application.Electrochemical testing results show that the Pb-C negative plate,which is made by anode composite carbon material as the carbon source of in-situ synthesis of chitosan, possessing better electrochemical performance and smaller resistance.Its specific capacitance of cyclic voltammogram test is 162.9F/g with longer first discharge platform,the ultimate capacity reaches to 108.722mAh·g-1 when chitosan as carbon source, the specific capicity is 98% of the theoretical capacity. After 1000times of cycle there is almost no decay in capacity.

Flexible and foldable microcomponents are highly desirable for energy devices. In this work, flexible asymmetric micro‐capacitor (AMC) is fabricated by using uniform Ag/Bi2S3 (or Bi2S3) nanoflowers, active carbon and carbon fibres are used as positive material, negative material and current collector, respectively. On one hand, the areal capacitance of Ag/Bi2S3 electrode has increased by more than 6 times than Bi2S3, and 86 and 68% of capacitances are retained for Ag/Bi2S3 and Bi2S3 electrodes after 4000 cycles, respectively. On the other hand, Ag/Bi2S3‐based AMC has an energy density of (0.0134 mWhcm−3) 4.36 times higher than Bi2S3‐based one (0.0025 mWhcm−3); after 4000 cycles, 84 and 33% of capacitances are retained for Ag/Bi2S3‐ and Bi2S3‐based AMCs, respectively. The improved performances are mainly attributed to the enhanced electrical conductance by Ag loading (Bi2S3: 21.898 Ω; Ag/Bi2S3: 4.5643 Ω). Most importantly, the AMC is flexible and foldable, which is promising to conveniently apply in complicated energy devices, production for practical applications. [ABSTRACT FROM AUTHOR]

Sisal is a perennial tropical biomass with largest dosage in industry. Due to the special hard structure of sisal fiber, it can be prepared as carbon material and applied for negative material of lead-carbon battery. The pretreatment of sisal fiber was carried out by 5% NaOH and 5% H 3 PO 4 and tested by the measurement of FTIR, thermogravimetric analysis and SEM. Carbazole was doped in pretreated sisal fiber to prepare carbon material by a simple approach with two-step method. The characterization of the synthesis doped-N carbon material was tested by Raman, BET, XRD and EDS. According to the result of BET, it was turned out that the doped-N carbon material had a larger specific surface area. And the electrochemical properties were measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Besides, the cycling life test and charge/discharge curve were performed on battery testing instrument. In addition, the lead-carbon battery contained doped-N carbon material had a longer discharge plateau and a higher ultimate capacity. It was concluded that doped-N carbon material had a better electrochemical performance compared to undoped-N carbon material. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cellulose-based biofilm is produced from soybean meal. • The biofilm was translucent. • The biofilm was used as a negative part of the TEG device. • The maximum outputs of TEG devices were 28 V and 80 nA. • TEG could light up three commercial LEDs. The residue from soybean production was used as starting materials for triboelectric energy generators (TEG). The soybean meal, cellulose, carboxymethyl cellulose (CMC), and biofilm were synthesized. FTIR spectra indicated functional groups of cellulose in all samples. The loss of the functional group in biofilm was observed by TGA spectra. The light absorption of biofilm was different from the others. The biofilm from soybean meal was used as a negative part of the TEG. The TEG generated a maximum output voltage of ∼28 V and a current of ∼80 nA and lit up three commercial LEDs. The results suggested the potential for waste usage from soybean production in triboelectric energy harvesting. [ABSTRACT FROM AUTHOR]

Abstract: Co/CMK-3 composites are synthesized via a facile hydrothermal route. The electrochemical performances of Co/CMK-3 composite as the negative electrode material for alkaline rechargeable Ni/Co batteries have been systemically investigated. Electrochemical measurements show that the CMK-3 can remarkably enhance the electrochemical activity of Co, leading to a notable improvement of the discharge capacity, cycle stability and rate capability. Interestingly, the discharge capacity of Co/CMK-3 (25 mg CMK-3) electrode can reach 519.3 mAh g−1 and retains about 365.8 mAh g−1 after 100 cycles at discharge current of 100 mA g−1. The electrochemical reaction mechanism of Co/CMK-3 composite electrode can be attributed to the electrochemical redox reaction between Co and Co(OH)2. [Copyright &y& Elsevier]

Tin-based oxide Li2SnO3 has been synthesized by a hydrothermal route as negative material for lithium-ion batteries. The microstructure and electrochemical properties of the as-synthesized materials were investigated by some characterizations means and electrochemical measurements. The as-synthesized Li2SnO3 is a porous rod, which is composed of many uniform and regular nano-flakes with a size of 50-60 nm. Li2SnO3 also displays an electrochemical performance with high capacity and good cycling stability (510.2 mAh g−1 after 50 cycles at a current density of 60 mA g−1 between 0.0 V and 2.0 V verusus Li/Li+). Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We study a 2D scalar harmonic wave transmission problem between a classical dielectric and a medium with a real-valued negative permittivity/permeability which models an ideal metamaterial. When the interface between the two media has a corner, according to the value of the contrast (ratio) of the physical constants, this non-coercive problem can be ill-posed (not Fredholm) in 1. This is due to the degeneration of the two dual singularities which then behave like r±iη = e±iη r with η ∈ ℝ*. This apparition of propagative singularities is very similar to the apparition of propagative modes in a waveguide for the classical Helmholtz equation with Dirichlet boundary condition, the contrast playing the role of the wavenumber. In this work, we derive for our problem a functional framework by adding to 1 one of these propagative singularities. Well-posedness is then obtained by imposing a radiation condition, justified by means of a limiting absorption principle, at the corner between the two media. [ABSTRACT FROM AUTHOR]

Abstract: Spray drying method has been successfully applied to the field of lead-acid batteries. Lead powder/carbon black composite can be obtained by spray drying and subsequent calcination process. Glucose is added to increase the adhesion of carbon black and lead powder. The morphology changes before and after calcination are examined by FE-SEM. The composite negative material can enable the sum of discharge capacity increased by 8.27% from 4374.855 Ah to 4736.706 Ah at a discharge current of 25 A after 66 cycles. And the charge acceptance of the test cell also can be obviously enhanced. [Copyright &y& Elsevier]

Abstract: A series of pitch modified hard carbons was prepared using coal-tar pitch and phenolic resin as carbon precursors. The effects of the amount of the soft carbon from pitch precursor, varying from 0wt% to 40wt%, and heat-treatment temperature in the range from 900°C to 1800°C, on their electrochemical performance were systemically studied, including the reversible capacity, coulombic efficiency in the first cycle, the rate capability and cycling stability. Under the optimal condition, the carbon material obtained at 1200°C with 30wt% soft carbon as negative material for lithium-ion batteries exhibits a reversible capacity of about 290mAhg−1 at a constant current density of 0.5mAcm−2 with excellent rate capability and cycling stability. [Copyright &y& Elsevier]

Abstract: A silicon/disordered-carbon powder was applied as the negative electrode material in Li ion batteries. The thermal characteristics of the Si/C electrode mixed with or without the electrolyte were investigated by DSC. Both lithiated (with capacity of 1120mAhg−1) and delithiated Si/C electrode powder showed exothermic peaks in DSC curves due to the reactions between the Li in the electrode and the SEI. The lithiated electrode caused much larger exothermic heat than the delithiated one, especially when they were mixed with the electrolyte. By changing the ratio between the lithiated Si/C electrode and the coexisting electrolyte, the thermal behavior of the mixture could be studied in detail. At about 290°C, a mixture containing 0.5mg lithiated Si/C electrode and 0.5μl electrolyte showed the most drastic exothermic heat of 2.2J among all mixtures due to a direct reaction between the residual lithiated electrode and the solvent of the electrolyte after the thermal breakdown of the SEI. Under this condition, the heat value based on the electrode weight was 4.4Jmg−1, and that based on capacity was 5.1JmAh−1. These values of graphite were estimated to be 1.9Jmg−1 and 5.8JmAh−1, respectively. The generated heat was found to be very sensitive to the electrode/electrolyte ratio. [Copyright &y& Elsevier]

Abstract: Si–SiO2–C composites are synthesized by ball milling the mixture of SiO, graphite and coal pitch, and subsequent heat treatment at 900°C in inert atmosphere. The electrochemical performance and microstructure of the composites are investigated. XRD and TEM tests indicate that the carbon-coating structure of Si–SiO2–C composites form in pyrolysis process, which can remarkably improve the electrochemical cycling performance. The coal pitch as carbon precursor and graphite demonstrate the same important effect on the Li-alloying/de-alloying property of the Si–SiO2–C composites. The Si–SiO2–C composites exhibit the electrochemical reversible Li-alloying/de-alloying capacity of 700mAhg−1 and excellent cyclic stability even at about the 90th cycle. [Copyright &y& Elsevier]

The Fe 3 C is nanocrystallized and stabilized by core–shell structure. The scattered core–shell cells are integrated together by rGO to build a complete electrode with high conductivity. The assembled hybrid supercapacitor delivers a high energy density as 84.8 Wh kg−1 with the power density of 840 W kg−1. [Display omitted] • In-situ grow a Fe 3 C-based core–shell architecture on the surface of reduced graphene oxide, under melamine atmosphere. • Fe 3 C in the formation of nanocrystallization is encapsulated in the separate N-doping carbon "room". • The elaborate construction improves the rate ability and stability of supercapacitor. • The resultant electrode can be suitably used as a negative electrode, and the assembled device delivers high energy density. Herein, we synthesize a hybrid negative electrode (Fe 3 C@NC/rGO) by using the ammonium ferric citrate (AFC) as Fe-source, under melamine atmosphere, in-situ growing the core–shell architecture, in which the Fe 3 C particles are encapsulated into the N-doping carbon (NC) shell on the surface of reduced graphene oxide (rGO). Resulting from the dual effect of NC and rGO, the Fe 3 C@NC/rGO exhibits high specific capacitance of 1091.9F g−1 at 10 mV s−1 (70% capacitance retention when the scan rate increased to 100 mV s−1) and long-term stability (96% capacitance retention after 8000 cycles), which outperforms all Fe-based electrodes reported so far in aqueous electrolytes. The Fe 3 C@NC/rGO-5 as negative electrode is matched with CNT-Ni(OH) 2 positive electrode to fabricate an aqueous asymmetric supercapacitor (ASC). Based on the larger potential difference between peak potentials of the negative and positive electrodes, the assembled ASC can deliver the energy density of 84.8 Wh kg−1 along with the power density of 840 W kg−1 (the maximum power density could reach up to 42 kW kg−1), and shows only 2.3% capacitance decay after 10,000 cycles. Two assembled ASCs in series can easily light 55 LEDs. [ABSTRACT FROM AUTHOR]

Based on theoretical analysis and experiments, the low-pass filter effects of the μ-negative materials/double positive materials/μ-negative materials (MNG-DPS-MNG) surface plasmon polaritons waveguide are studied by using L-C loaded transmission line structures in microwave band. It is shown that the pass-band width of the waveguide is not determined by its size but the effective permeability in MNG materials. So it can be used to realize the small size and tunable low-pass filter. The experimental results are in good agreement with results of simulations. These properties will have potential application values in the miniature and tunable low-pass filters. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1531-1533, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27627 [ABSTRACT FROM AUTHOR]

SnO 2 is regarded as a promising negative material candidate for contemporary lithium-ion batteries (LIBs). However, the nanostructured SnO 2 electrodes suffer from rapid capacity fades during lithiation and delithiation at a high-current density due to active materials aggregating and cracking. Herein, we designed and fabricated a novel multilayered hollow TiO 2 @SnO 2 @C sphere electrode though a facile three-step sol-gel coating process and hydrothermal strategy. The SnO 2 nanoparticles are well confined between an outermost high-conductivity carbon layer and innermost stable hollow TiO 2 nanospheres that form the pillar structure of the entire composite. Attributed to the internal spherical titanium dioxide as a support layer, the structural integrity of the composite and the possible anti-inward rupture can be effectively improved. As a result, the as-prepared TiO 2 @SnO 2 @C electrode exhibits a remarkable reversible capacity of 484 mAh g−1 at 0.2 A g−1 after 300 cycles and delivers outstanding capacity of 263 mAh g−1 at 3 A g−1. Moreover, this unique SnO 2 hollow sphere structure with TiO 2 as the innermost stable pillar will have implications for the design of high-power-density negative materials for future lithium-ion batteries. • A unique multilayered hollow TiO 2 @SnO 2 @C nanosphere has been fabricated. • The volume expansion of SnO 2 was effectively restrained by innermost TiO 2 and outermost carbon layer. • TiO 2 @SnO 2 @C delivers significant improved electrochemical performance at a high current density. [ABSTRACT FROM AUTHOR]